glog.diff

diff --git a/src/saveload/gamelog_sl.cpp b/src/saveload/gamelog_sl.cpp
index 6bff1b154..f8df687ab 100644
--- a/src/saveload/gamelog_sl.cpp
+++ b/src/saveload/gamelog_sl.cpp
@@ -107,8 +107,12 @@ static void Load_GLOG_common(LoggedAction *&gamelog_action, uint &gamelog_action
        assert(gamelog_action == nullptr);
        assert(gamelog_actions == 0);
 
+       byte type;
        GamelogActionType at;
-       while ((at = (GamelogActionType)SlReadByte()) != GLAT_NONE) {
+       while ((type = SlReadByte()) != GLAT_NONE) {
+               if (type >= GLAT_END) SlErrorCorrupt("Invalid gamelog action type");
+               at = (GamelogActionType)type;
+
                gamelog_action = ReallocT(gamelog_action, gamelog_actions + 1);
                LoggedAction *la = &gamelog_action[gamelog_actions++];
 
@@ -119,7 +123,10 @@ static void Load_GLOG_common(LoggedAction *&gamelog_action, uint &gamelog_action
                la->changes = 0;
 
                GamelogChangeType ct;
-               while ((ct = (GamelogChangeType)SlReadByte()) != GLCT_NONE) {
+               while ((type = SlReadByte()) != GLCT_NONE) {
+                       if (type >= GLCT_END) SlErrorCorrupt("Invalid gamelog change type");
+                       ct = (GamelogChangeType)type;
+
                        la->change = ReallocT(la->change, la->changes + 1);
 
                        LoggedChange *lc = &la->change[la->changes++];
@@ -127,8 +134,6 @@ static void Load_GLOG_common(LoggedAction *&gamelog_action, uint &gamelog_action
                        memset(lc, 0, sizeof(*lc));
                        lc->ct = ct;
 
-                       assert((uint)ct < GLCT_END);
-
                        SlObject(lc, _glog_desc[ct]);
                }
        }